Anyone who watches the Simpsons or Ghostbusters (555 2368) is aware that numbers beginning with 555 in the states are usually fake. While looking for information about international dialing from the UK, I stumbled upon the official Ofcom list of fake numbers - UK number ranges reserved for drama purposes.
In most areas in the UK, a 496 number is fake - however there is an entirely fictitious area code of 01632 and even reserved number ranges for mobiles, premium rate and even freephone services. Who would have expected them to be so organised!
A quick check over at Wikipedia gives an interesting article on the use of Fictitious phone numbers including gems of information such as both 24 and Scrubs use numbers that go through to production staff. The Scrubs one is (apparently) answered by a voicemail message given by one of the cast in character.
Hmm, maybe I should ask that my extension at work get changed from 42 to 555...
Thats cool - I just took some photos of a phone booth being used as a prop for the new series of Wire In The Blood (Robson Green TV Show) fillming in Newcastle. It had some 'adult calling cards' in and I'm sure the numbers started with 01632.
Damn, that means they're not real :(